1. Field of the Invention:
This invention relates to a tire bead breaker and in particular to a bead breaker which is portable.
2. Prior Art:
There have always been certain problems in removing vehicle tires from rims as it is necessary to break the seal between the bead and the rim.
When tires were invariably tubed the rims tended to have a flat surface on which the tire rested and it was possible to break the seal between the tire and the rim, simply by provided an axial force which could be obtained by some form of pressure means or even by inserting a tire lever between the tire and the rim and then causing this to move the tire inwardly.
As tire technology advanced and particularly with the onset of the tubeless tire the rim formation normally became more complex to ensure a good seal between the tire and the rim and the problem was exacerbated.
There have previously been proposed a number of different bead breakers, many of which are fixed and use hydraulic or pneumatic pressure to provide substantial axial forces to the tire and in all cases the wheel and tire are held against tilting movement relative to the axis whilst in many cases it is possible to rotate the wheel about the axis while the bead is being broken.
There have also been proposed certain portable bead breakers and one such device is illustrated in Australian Patent No. 487887 of Alec Muntro McGregor and, in this device also the wheel and tire remain flat during the operation of the device.
The desirability of having a portable bead breaker has increased with the advent of more leisure, which means that more motorists tend to visit areas away from tire and/or service stations and specifically with the increased use of 4-wheel drive vehicles for such use. The wheels and tires of 4-wheel drive vehicles are normally substantially larger and heavier than those of a normal automobile and these wheels and tires are consequentially more difficult to handle than the lighter automobile tires.